Winter Roost Boxes. Chickadees, owls, and woodpeckers that remain in Alaska during winter use natural tree cavities and birdhouses as roosting sites. These roosting sites provide protection from wind and snow and extra insulation against the cold. Any birdhouse can provide a winter roost site if it is properly built, but better insulated birdhouses can also be constructed. Try placing perches on the inside of a birdhouse. During severe cold several chickadees sometimes share their body heat by roosting together in a single cavity.